Add support for doctrine/annotations V2

[maxbaldanza]

Symfony 4.4 doesn't seem to work well with doctrine/annonations V2 due to the Framework extension calling registerLoader on AnnotationRegistry which is deprecated in V1 and then removed in V2.
This looks to have been fixed in Symfony5 but not been ported to 4.4 as it's no longer supported:
https://github.com/symfony/symfony/blob/650f7bd03e1ae36412b2099976831042472ae91c/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php#L1634-L1641